Quantum dot light-emitting diodes (QD-LEDs) have been considered as one of the promising candidates for light sources in display applications owing to their good color saturation, high brightness, spectral tunability, and low processing cost. Thus far, the performance of red and green QD-LEDs has been significantly improved by optimizing QD materials and device architectures and by gaining a further understanding of their luminescence mechanism. However, as one of the three primary color sources, the performance of blue QD-LEDs still lags behind that of red and green QD-LEDs. Herein, we review the recent research progress in blue QD-LEDs, including Cd-based QD-LEDs, perovskite-based LEDs (PeLEDs), and heavy-metal-free QD-LEDs. The advances in Cd-based blue QD-LEDs are firstly introduced, and the efficiency has been improved from less than 0.1% to ∼20% through the optimization of the components and surface ligands of QDs as well as the optimization of device architecture and interfacial engineering, and the aging mechanism of blue QD-LEDs is also discussed. Next, we review PeLEDs based on different types of perovskite materials, including two-dimensional (2D)/quasi-2D perovskites included in organic–inorganic halide perovskites and all inorganic perovskites. Currently, state-of-the-art PeLEDs fabricated from quasi-2D organic–inorganic perovskites exhibit the maximum external quantum efficiency (η_EQE) exceeding 11%. Furthermore, we summarize the research progress in heavy-metal-free blue QD-LEDs, which are fabricated from ZnSe, InP, Cu-based QDs and carbon dots. Although there is a huge gap in the device performance of heavy-metal-free LEDs as compared to the other two types of blue LEDs, the heavy-metal-free blue LEDs stand for a promising achievement toward their practical application. Finally, some challenges and possible development directions of blue QD-LEDs are suggested, which may speed up the further progress.

中文翻译：

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蓝色量子点基电致发光二极管

量子点发光二极管（QD-LED）由于其良好的色彩饱和度，高亮度，光谱可调性和低处理成本而被认为是显示应用中光源的有希望的候选者之一。到目前为止，通过优化QD材料和器件架构以及进一步了解其发光机理，红色和绿色QD-LED的性能已得到显着改善。但是，作为三种主要色源之一，蓝色QD-LED的性能仍然落后于红色和绿色QD-LED。本文中，我们回顾了蓝色QD-LED的最新研究进展，包括基于Cd的QD-LED，基于钙钛矿的LED（PeLED）和不含重金属的QD-LED。首先介绍了基于Cd的蓝色QD-LED的进展，并且效率从小于0提高到了0。通过优化QD的成分和表面配体以及优化器件的结构和界面工程来改善1％至20％，还讨论了蓝色QD-LED的老化机理。接下来，我们将基于不同类型的钙钛矿材料（包括有机-无机卤化物钙钛矿中包含的二维（2D）/准2D钙钛矿和所有无机钙钛矿）审查PeLED。目前，由准2D有机-无机钙钛矿制成的最先进的PeLED具有最大的外部量子效率（包括有机-无机卤化物钙钛矿和所有无机钙钛矿中包含的二维（2D）/准2D钙钛矿。目前，由准2D有机-无机钙钛矿制成的最先进的PeLED具有最大的外部量子效率（包括有机-无机卤化物钙钛矿和所有无机钙钛矿中包含的二维（2D）/准2D钙钛矿。目前，由准2D有机-无机钙钛矿制成的最先进的PeLED具有最大的外部量子效率（η _EQE）超过11％。此外，我们总结了由锌硒，铟磷，铜基量子点和碳点组成的无重金属蓝色量子点LED的研究进展。尽管与其他两种类型的蓝色LED相比，不含重金属的LED的器件性能存在巨大差距，但不含重金属的蓝色LED仍在其实际应用中取得了可喜的成就。最后，提出了蓝色QD-LED的一些挑战和可能的发展方向，可以加快进一步的发展。